1. Field
The disclosure relates generally to semiconductor devices and, in particular, to metal-oxide-semiconductor (MOS) transistors.
2. Background
High-voltage MOS (HVMOS) transistors play an important role in wireless communication today. For example, a wireless device (e.g., a cellular phone or a smart phone) may transmit and receive data for two-way communication with a wireless communication system. The wireless device may include a transmitter for data transmission and a receiver for data reception. For data transmission, the transmitter may modulate a transmit local oscillator (LO) signal with data to obtain a modulated radio frequency (RF) signal, amplify the modulated RF signal to obtain an output RF signal having the desired output power level, and transmit the output RF signal via an antenna to a base station. For data reception, the receiver may obtain a received RF signal via the antenna, amplify and downconvert the received RF signal with a receive LO signal, and process the downconverted signal to recover data sent by the base station.
Typically, the RF functions operate at a higher voltage than the digital portions of the chipset within the wireless device. Because a higher breakdown voltage is needed, the HVMOS transistors may be utilized to provide power to the RF functions. However, those HVMOS transistors may not be integrated with the digital portions of the chipset within the wireless device. In one example, HVMOS transistors may require special steps and materials in the fabrication process. The HVMOS transistors would thus need to be fabricated separately from the digital components, adding to the manufacturing cost and consuming precious space within the wireless device.